Fendel began her acting career on stage in 1946, appearing at the Kammerspiele in Munich as a flower girl in a production of Girodoux's "Die Irre von Chaillot".
[2] She was noticed by director and actor, Gustaf Gründgens, who brought her to act in productions in the Düsseldorfer Schauspielhaus as well as to perform in Darmstadt, Munich and Frankfurt.
Towards the end of her career, she routinely gave private and small performances of works by Goethe and Mascha Kaléko, often in her home in Frankfurt.
[4] Other notable film roles include Alle Jahre wieder (1967), Tätowierung (1967), Dream City [de] (1973), Ödipussi (1988), Schtonk!
[6] In 1973, Fendel assisted her long-time partner, director Johannes Schaaf, in writing the screenplay for his film Dream City [de].
[7] During her retirement from the stage, Fendel worked as a voice actor and performed roles by Elizabeth Taylor, Jeanne Moreau, Simone Signoret, Lauren Bacall, Anne Bancroft, Myrna Loy, Dorothy Parker, Vanessa Redgrave, and Annie Girardot in German dubs.